Tampon applicators which include a pair of telescoping cylinders are well known in the art. For example, Berger, U.S. Pat. No. 3,895,634, assigned to the assignee of the subject application, and Voss U.S. Pat. No. 3.433,225 typically show such applicators in Which the pledget is initially stored in the forward end of a cylindrical barrel. A lesser diameter plunger is telescopingly contained within the rear end of the barrel, such that the forward end of the plunger abuts the rear end of the pledget. Advantageously, the forward end of the barrel, which is inserted in the vagina prior to tampon injection, includes a smooth, dome-shaped end for user comfort. When the user then urges the plunger against the rear end of the pledget, the pledget is moved forwardly in the barrel, opening up the petals which form the dome-shape forward end of the barrel, as the pledget is ejected from the barrel. Following the full ejection of the tampon pledget, the petals then return towards their original closed position so as to comfortably remove the applicator from the body orifice.
Such tampon applicators are conventionally manufactured either of a suitable plastic composition, which is typically ejection molded, or from cardboard. In view of environmental concerns, cardboard applicators, which are water degradable or water dispersible, are increasingly desirable.
After such tampon applicators are fully assembled at the manufacturing location and shipped to the ultimate retail outlet, there is usually a prolonged duration of time between original manufacture and use. It has been observed that during this period there is a tendency of the individual cardboard petals forming the tip to open somewhat. The degree to which the petals open is referred to as petal tip stability. It is believed that this partial opening after being formed into their curved dome-shaped configuration is due to the memory of the cardboard which tends to urge the petals towards their initial open condition.
If the petal tips are not sufficiently stable, their premature opening prior to pledget ejection can result in an undesirable and oftentimes unacceptably uncomfortable insertion. Accordingly, it is desirable to effectively maintain the petals of the dome tip in a formed position prior to the user urging the telescoping plunger forward to intentionally eject the pledget through the dome shape forward tip of the barrel.
While various techniques have previously been proposed for modifying the forward end of dome-shaped cardboard applicators, none have been found to achieve the requisite increased stability in accordance with the other desirable applicator parameters. Hence, the increased stability achieved by the instant invention can be combined with other techniques for reduced ejection force and cardboard petal tip shaping so as to advantageously provide a tampon applicator tip construction which a) may be readily formed to its desired configuration, b) experiences a sufficiently low ejection pressure for ease of consumer use, and c) provides a high degree of petal tip stability for maintaining the tip configuration from the time of manufacture to the time of use. For example, my method for increased tip stability may be used in conjunction with the method for reducing the force for ejecting the tampon pledget through a petal tip applicator, as is the subject of Rejai U.S. patent application Ser. No. 07/886,114 filed on even date herewith and assigned to the assignee of the instant application. Other petal tip forming techniques which may be practiced in conjunction with the instant invention are disclosed in Wiegner, et al. U.S. Pat. No. 4,412,833 and Beastall et al. U.S. Pat. No. 4,087,239 which provide an indented circumferential groove (which can take the form of slots or perforations in Beastall) at the base of the cardboard petals to provide a hinge region for the bending of the petals. Such a hinge had also been disclosed in aforementioned Voss et al. U.S. Pat. No. 3,433,225. The petal tips may also include a series of transverse score or relief lines along the length of the cardboard petals to facilitate their bending into a round tip as shown in Whitehead U.S. Pat. No. 4,508,531 and Decker U.S. Pat. No. 4,453,925.
Further, recognizing that some variations are to be expected in the mass production of tampon applicators, as for example resulting from the characteristics of the cardboard or tip shaping, the enhanced petal tip stability provided by my invention, insures that appropriate performance will be achieved within the anticipated range of product manufacturing variations.